1. Field of the Invention
The present invention relates to switching power supplies. In particular, the present invention relates to a switching power supply with a protection function, which can protect a load from damage.
2. Description of Related Art
Pulse width modulation (PWM) is traditionally used in a switching power supply to control output power and achieve regulation. Equipment such as mobile phones and computers use a PWM controller to supply power and charge batteries.
A conventional switching power supply uses a PWM controller to receive a feedback voltage, then adjust the duty ratio of a PWM signal to adjust the output voltage to a predetermined voltage. However, there is a brief period when the output voltage is unstable before it is adjusted to the predetermined voltage. If the unstable output voltage is directly provided to a load, such as a light emitting diode (LED), it can damage the load or decrease the useful lifetime of the load.
What is needed is a switching power supply system with a protection function that can protect a load from damage.